Glycosylated Hemoglobin Test
(HbA1c; GHb; Glycohemoglobin; Diabetic Control Index)
Definition
A glycosylated hemoglobin test (HbA1c) is a blood test that measures the amount of glycosylated hemoglobin in the blood. Hemoglobin is a protein found in the blood. Glycosylated hemoglobin means that glucose (sugar) has attached to the hemoglobin protein. The higher your blood sugar is, the more that glucose gets attached to your hemoglobin.
Glycohemoglobin
Reasons for Test
HbA1c shows how high your blood sugar levels have been during the past three months. This can help your doctor determine how well you are controlling your diabetes. Your doctor may also use HbA1c to test you for diabetes.
Possible Complications
There are no major complications associated with this test.
What to Expect
Description of Test
You will roll up your sleeve. An elastic band will be wrapped around your upper arm. An area on your arm will be cleaned with alcohol. The needle will then be inserted into your arm. A small amount of blood will be drawn into a tube. The needle will be removed. Pressure will be applied to the puncture site. A small bandage may be placed on the site. Your blood will be sent to a lab for testing.
Call Your Doctor
After the test, call your doctor if any of the following occurs:
- Bleeding from the puncture site
- Red, swollen, or painful puncture site
- If you have not heard from your doctor in 1-2 weeks
American Diabetes Association
National Diabetes Education Program
Canadian Diabetes Association
Health Canada
A1C Test. Mayo Clinic website. Available at: http://www.mayoclinic.com/health/a1c-test/MY00142. Updated January 21, 2011. Accessed July 31, 2012.
American Diabetes Association. Standards of medical care in diabetes—2008. Diabetes Care. 2008;31:S12-S54.
Aronow WS, Ahn C, Weiss MB, Babu S. Relation of increased hemoglobin A1c levels to severity of peripheral arterial disease in patients with diabetes mellitus. Am J Cardiol. 2007;99:1468-1469.
Check your hemoglobin A1c IQ. National Diabetes Education Program website. Available at: http://nfb.org/Images/nfb/Publications/vodold/vspr9905.htm. Accessed July 31, 2012.
A new number. American Diabetes Association website. Available at: http://forecast.diabetes.org/magazine/features/new-number. Accessed July 31, 2012.
Pradhan AD, Rifai N, Buring JE, Ridker PM. Hemoglobin A1c predicts diabetes but not cardiovascular disease in nondiabetic women. Am J Med. 2007;120:720-727.
Saudek CD, Herman WH, Sacks DB, et al. A new look at screening and diagnosing diabetes mellitus. J Clin Endocrinol Metab. 2008;93:2447-2453.
Standards of medical care in diabetes mellitus. American Diabetes Association website. Available at: http://care.diabetesjournals.org/content/26/suppl_1/s33.full. Accessed July 31, 2012.
Last reviewed September 2012 by Brian Randall
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
